This article describes how dental adhesives evolved from the cements developed by the Mayan Indians into today's modern dental adhesives. Particular attention is paid to Oskar Hagger, a chemist who worked for DeTrey/Amalgamated Dental Company, and already in 1949 developed an adhesive product called Sevriton Cavity Seal. That adhesive was acidic and interacted with the tooth surface on a molecular level. His ground-breaking concept makes him the true "Father of Modern Dental Adhesives." Hagger's concept was soon adopted by other investigators, and different generations of dental adhesives evolved thereafter. Today, after many years of accepting that the key to the success of dental adhesives is the micromechanical retention resulting from acid etching of dentin and enamel, we still return to Dr. Hagger's original concept that bonding can be achieved via molecular interactions between adhesives and tooth surfaces. That concept is obvious in the development of newer generations of dentin adhesives. These adhesives, like Sevriton Cavity Seal, rely on acidic monomers capable of etching and interacting on a molecular level with tooth surfaces in order to form physical/chemical bonds between the restoration and the tooth. Whether Hagger's concept will become the norm in the future is still an open question, but one thing is certain: Hagger's idea is still very much alive. Keywords: review, generations, clinical evaluations